Traffic controlling system for railroads



SeptZZ, 1931.- A. LANGDON TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed Oct. 30, 1950 INVENTOR @ATTQRNEY Patented Sept. 22, 1931 UNITED STATES ANDREW LANGDON, ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY f PATENT OFFICE SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Application filed. ctober 30, 1930.

This invention relatesto'traffic controlling system for railroads, and more particularly pertains to the remote control of railroad track switches and the indication of their '5 position at the control point.

In one type of remote control for railroad track switches, a power operated switch machine is governed by a polar relay which is controlled over a polarized line from the to central tower. In a system of this type it is desirable to have the polar relay at the switch machine normally deenergized in order to reduce the power consumption.

One feature of the present invention is to provide a remote control system for railroad track'switches of the type above described with means for utilizing the normally deenergized line wires for indicating in the tower the position of the associated 2'9 track switch.

Other objects, purposes and characteristic features of the present inventionwill be in part obvious from the accompanying drawing and in part pointed out as the de 2 scription of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawing which illustrates in a diagrammatic manner one form which the present invention may assume. 7

lVith reference to the drawing, a railroad track switch TS is indicated as controlled by a suitable switch machine SM. This switch machine may be of any suitable type adapted to be locally controlled by a control relay CR which applies energy to normal or reverse control wires N or R from a suitable source such as battery BT to thereby operate the track switch to normal or reverse positions respectively.

The control relay GR is preferably of the polar mechanical stick type, where its contacts are operated to one or the other of twO extreme positions in accordance with the polarity applied to its actuated winding, and remain in such positions due to a toggle device or other holding means although its actuating winding is subsequently deener-- gized.

The switch machine SM includes a'group of Serial No. 492,281.

point detector contacts of any suitable type, such for example as shown in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 192e, which in this case have been I the track switch TS is unlocked or is being i operated by the switch machine SM, and assume opposite extreme positions when the track switch TS is in a reverse position and locked. The point detector contacts serve to change the relative polarity of alternating current suppliedto the primary of a transformer T as received from an alternating current transmission line extending from the tower. Two line wires extending from the tower are connected to the opposite terminals of the relay CR. The secondary of the transformer T is connected in series with one of these line wires and a condenser C is connected in multiple with the control relay OR for reasons hereinafter pointed out.

In the tower, a lever L is provided so that the operator may control the track switch TS from a normal extreme locked position to a reverse extreme locked position or vice versa. Contacts 7 and 8, associated with the lever vL, are moved from normal extreme positions (as shown) to reverse dotted line positions in accordance with the corresponding movement of the lever L for the purpose of pole changing the current supplied from a battery B to the line wires extending to the relay CR. A contact 9 is likewise operated by the lever L and makes contact with a fixed contact while passing through a center position when the lever L is moved from one extreme position to the other. i

A slow acting lock relay LR is provided for connecting the line wires extending from the relay CR to elther the governing contacts '7 and 8, orto the line phase winding of an indicating relay IR. The indicating relay IR is of the two phase alternating current type having a local phase winding 10 which receives energy from the alternating current transmission line. This indicating relaylR is preferably of the three position induction type relay having its operation dependent upon the relative phase displacement between the line phase winding and the local phase winding, to thereby control a contact 11 to one or the other of two extreme positions when both phase windings of the relay are energized. If one or the other of the windings of the relay IR are deenergized, the contact 11 assumes a deenergized position.

Operation of the system With the track switch TS in a normal extreme locked position as shown, alternating current of one relative polarity is supplied to the primary of the transformer T through a circuit from the alternating current transmission line through wires 15 and 16, contact 5 in a normal position, wire 17, primary of transformer T, wire 18, contact 6 in a normal position, wire 19. back to the transmission line. This energization of the transformer T supplies alternating current of one relative polarity to the line phase winding of the indicating relay IR through circuit traced as follows :from the left hand terminal' of the secondary of transformer T, through wire 20, back contact 21 of relay LR, wire 22, line winding of the relay IR, Wire 23, back Contact 24 of relay LR, wire 25, condenser C, wire 26, to the right hand terminal of the transformer T. The current which flows in this energizing circuit of the line phase winding of the relay IR causes the contact 11 thereof to be operated to a left hand full line position by reason of its phase displacement with respect to the current in the local phase winding 10. As the winding of the relay GR is designed for direct current, its impedance to alternating current is extremely high in comparison to the impedance of the condenser C, thus the alternating current flows in the circuit as traced and does not efiect the operation of the control relay CR. This result may be accomplished by other means, such for example as the use of a non-inductive resistor or the like. hus, the invention is not limited to the use of a condenser. I

With the track switch TS in a normal extreme locked position, the contact 11 of the indicating relay IR is actuated to a left hand position. thereby permitting the selection of such circuits as are desirable to be governed in accordance with the position of the track switch .TS. The selected circuits have not been shown as such circuits may govern lever operation, signal controls andthe like in accordance with the usual signalling practices, well understood by those skilled in the art. 7 1

Let us assume that theoperatormoves the lever L fromthe normal position shown to a reverse dotted line position, which operation moves the contacts 7 8 and 9 to reverse dotted line positions. During the passage of the contact 9 from one position to the other, a circuit is momentarily completed for the relay LR from the positive terminal of a suitable source of electrical potential indicated as through contact 9, wire 82, winding of relay LR, to the opposite termi nal of the suitable source indicated as The relay LR is of the quick pick-up and slow releasing type so that its contacts 21 and 2a are actuated to energized positions by reason of the circuit just traced, but the relay LR remains energized for a suiiicient length of time to allow the circuit completed through its front contacts 21 and 24 to energize the control relay GR in accordance with the position of the lever contacts 7 and 8.

However, it is to be understood in this connection that any suitable control of the lock relay LR may be employed, such for example as shown in. my pending application, Ser. No. 467,283 filed July 11, 1980 where the lock relay. LR is controlled in accordance with trailic conditions and also in accordance with the position of the indicating relay IR relative to the position of the control lever L. Also, it is further noted that the lock relay LR could be controlled in a manner as set forth in the pending application of S. N. Vight, Ser. No. @67222, filed July'll, 1930. The control of therelay LR shown in the ac companying drawing is more for the purpose of illustrating the fact that the relay LR is energized whenever the control lever L assumes a new position, rather than setting forth the specific control which'may best be employed therewith.

During the energization of the relay LR, energy is supplied to the control relay CR from the battery Bthrough wires 33 and 34, contact 8 in. a dotted line position, wire 35, front contact 21 of the relay LR, wire 20, secondary winding of the transformer T, wires 26 and 30, winding of relay CR, wires 31 and 25, front contact 24 of relay LR, wire 86, contact Tin a dotted line position, wire 37, to the opposite terminal of the battery B. This application of the opposite polarity to the relay CR causes its contact 38 to be operated to a dotted line position, thereby apply-.

ing positive energy from the battery BT through contact 38 of relay CR to the reverse operating wire of the switch machine SM.

The switch machine in response thereto un-' of the primary of transformer T. Thus, the contacts of the relay IR assume deenergized intermediate positions as soon as the relay LR is energized and remain deenergized until the point detector contacts assume extreme positions subsequent to the decnergization of the relay LR.

Upon the completion of the operation of the track switch TS, the contacts 5 and 6 assume reverse extreme positions thereby supplying the primary of transformer T with the opposite relative polarity. It is obvious that the transformer T now supplies energy of the opposite relative polarity to the energizing circuit of the relay IR (with relay LR now deenergized) which causes its contact 11 to be operated from an intermediate position to a right hand dotted line position by reason of the reversed phase displacement. Those circuits which are to be governed in accordance with the position of the track switch TS are thereby properly selected.

The operation of the system from a reverse condition to a normal condition is merely the converse of that operation already described and will not be given.

It is noted. that -for a short time during the energization of the relay LR before the track switch is unlocked resulting in the movement of contacts 5 and 6 to an intermediate position, the alternating current supplied by the secondary of the transformer T passes through the battery 13. This is not objectionable with certain constants or values employed within the circuit, however, with certain combinations of apparatus it might be desirable to prevent or limit such flow of alternating current by additional means which may be adequately provided for by including an alternating current impedance in series in the wire 37. Such an impedance should have high inductance but very low ohmic resistance to prevent the flow of alternating current without hindering the efficient operation of the relay CR.

Having described a remote control and indication system for a railroad track switch as one specific embodiment of the present invention, it is desired to be understood that this arrangement is select-ed to facilitate in the disclosure of the invention rather than to limit the number of forms and arrangements which it may assume; and, it is to be further understood that various modifications (other than those mentioned), adaptations and alterations may be applied to the specific form shown to meetthe requirements of practice, without in any 1nauner departing from the spirit and scope of the present invention except as limited by the appended claims.

Having described my invention, I now claim i 1. In combination, an electro-responsive device responsive to direct current only, a circuit for said electro-responsive device, a source of alternating current at times connected in said circuit, a source of direct current, another electro-responsive device responsiveto alternating current only, and means at times connecting said circuit to said another electro-responsive device and at times connecting said circuit to said direct current source.

2. In combination, one electro-responsive device responsive to one type of current, another electroresponsive device responsive to another type of current, a lock relay, a circuit connecting said one and said other electro-responsive device when said lock relay is deenergized, means included in said circuit for energizing only said other electro-responsive'device with said other type of current, a source of said one type of current, and another circuit connecting said source to said one electi'onesponsive device when said lock relay is energized,

3. In combination, a switch machine, a di-v rect: current polar responsive device for operating said switch machine, a control lever in a central tower, a line circuit extending from said polar device to said tower, a noninductive resistor connected in multiple with said polar device, an indicating relay responsive to alternating current only,'a.lock relay, means operated by said lock relay for. connecting said line circuit to either said indicating relay or said control lever, and means supplying said line circuit with alternating current in accordance with the position of said switch machine;

. 4. In combination, a railroad track switch,

a' central tower, two line wires extending from said switch to said tower, a control re-. lay connected to said line wire at said switch, a control lever in saidtower, an indicating relay in "said tower, means connecting said line wires to said lever or said indicating relay in accordance with the movement of said control lever, means at said tower for energizing said control relay in accordance with said lever, and means at said switch for energizing said indicating relay in accordance with the position of said switch.

5. In combination, a railroad track switch, a tower, a control circuit extending from said switch to said tower,'a control relay connected to said control circuit at said switch, a transformer 1 having a secondary winding connected in series with said control circuit, a condenser connected in multiple with said control relay, means for supplying alternating current to the primary of said transformer in accordance with the position of said switch, a control lever in said tower, an indicating relay in said tower, and a lock relay for connecting said control circuit to either said indicating relay or said control lever.

6. In comhinatiom'a railroad track switch, a switch machine, point detector contacts, a direct current control relay, a battery source, a control lever, a lock relay, an alternating current indicating relay, a circuit for energizing said direct current control relay with one or the otherpolarity from said battery source in accordance with the position of said control lever when said lock relay is energized, a circuit for shunting said control relay with said alternating current indicating relay when said lock relay is deenergized, and means superimposing alternating current on said shunting circuit in accordance with said point detector contacts.

7. In combination, a railroad track switch, a switch machine, point detector contacts, a direct current control relay, a battery source, a control lever, a lock relay, an alternating current indicating relay, a circuit for energizing said direct current control relay with one or the other polarity from said battery source in accordance with the position of said control lever when said lock relay is energized, a circuit for shunting said control relay with said alternating current indicating relay when said lock relay is deenergized,

' means superimposing alternating current on said shunting circuit in accordance with said point detector contacts, and means energizing said lock relay each time said control lever is moved to a new position in'accordance with traflioconditions.

8. In combination, a railroad track switch,

' a switch machine, point detector contacts, a

direct current control relay, a battery source, a control lever, a lock relay, an alternating current three position indicating relay having line and local phase windings, a circuitfor energizing said direct current control relay with one or the other polarity from said battery source in accordance with the posi-' tion of said control lever when said lock relay is energized, a circuit for shunting said control relay with the line phase winding of said alternating'current indicating relay when said lock relay is deenergized, means superimposing alternating current of one or the other relative polarity on said shunting circuit in accordance with said point detector contacts, and means energizing said lock relay each time said control lever and said indicating relay are out of correspondence.

In testimony whereof I aflix my signature.

ANDREW LANGDON. 

